Welcome from Kelowna and congrats on the new TT. I run with the Andersen hitch on our 28BHBE, but TV is a Silverado 3500HD. I find that the Andersen does NOT transfer all weight back to the front axle. Not so much an issue for an HD series truck, but i don't think it will work adequately with the Avalanche coil spring rear suspension. JMO.
We have used the bumper mount BBQ, but prefer the Coleman Roadtrip as we can have it closer to the rest of the cooking rather than on the other side of the bathroom door almost in the bushes